It has recently been shown by retinoscopy and by photorefraction that the eyes of infants are often astigmatic. These astigmatisms must usually disappear in the early years of life because the frequency and severity of astigmatism in adults is less than that found in infants. It has also been found by retinoscopy and confirmed by photorefraction that very young infants tend to be myopically focussed and that their ability to accurately focus distant objects increases over the first six months of life. The characterization of these changes in astigmatism and focussing ability in normal infants and young children is very important for the detection of abnormal refractive behavior and the prevention of amblyopia resulting from refractive errors. I propose to characterize the refractive development of infants and young children of various age groups using photorefraction, retinoscopy, and photokeratometry. The study will be latitudinal and longitudinal and should provide normative data for the detection of refractive anomalies in the first four years of life. A major question which the study will attempt to answer is whether early infant astigmatism is primarily corneal or lenticular in nature.